# SOLUTION: cos(x+(&#960;/2))-cos(2x)=0

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 Algebra: Trigonometry Solvers Lessons Answers archive Quiz In Depth

 Question 429870: cos(x+(π/2))-cos(2x)=0Found 2 solutions by robertb, Gogonati:Answer by robertb(4012)   (Show Source): You can put this solution on YOUR website! In the interval [0, ), either , or ==> , or , or (Same as the first solution.) Therefore the general solution is , where n is any integer. Answer by Gogonati(817)   (Show Source): You can put this solution on YOUR website!Solution:From the trigonometry we know that: , and cos(90+x)=-sin(x). Now we write: , substitute six=a and rewrite the equation: , which is a quadratic equation. Solve this equation: There are two roots: a=1 and a=-1/2, thus we have: sin(x)=1 and sin(x)=-12 Solve now these two trigonometric equations and find: x=2n*+ /2, x=2n*-/6, and x=2n*+/6 Done.